Scientific Forecaster Discussion
fxus66 khnx 241657
Area forecast discussion
National Weather Service San Joaquin Valley - Hanford California
957 am PDT Wed Apr 24 2019
..update to add isolated afternoon/early evening thunderstorms
to the Sierra crest today...
Synopsis...with the exception of isolated thunderstorms near
the Sierra crest this afternoon and again Thursday afternoon,
dry weather will rule over the central California interior
through Saturday with unseasonably warm temperatures. A storm
system will bring a chance of showers to mainly the higher
elevations of the district by late in the weekend along with
slightly cooler temperatures.
Discussion...unseasonably warm temperatures and moisture that
is readily available from melting snow over the High Sierra will
produce isolated thunderstorms near the crest this afternoon.
Convective parameters are marginally unstable in this region
later today with 700mb-500 mb rel humidity values above 70
percent, 850 mb dews above 8c and model CAPES approaching 1600
joules/kg. The convective potential could be a little higher
along the Sierra crest Thursday afternoon. The forecast was
updated accordingly and is in line with current Storm Prediction Center forecast.
No other changes were made to the short term periods.
Previous discussion... /issued 309 am PDT Wed Apr 24 2019/
a shortwave ridge axis will continue to move through the region
today as a larger broad Pacific Ridge begins to move into the
western Continental U.S. With temperatures across the area warming 3 to 5
more degrees than yesterday's highs. Across the San Joaquin Valley
and Kern County desert areas, high temperatures today will range
in the lower to mid 90s. The warmest temperatures will occur
tomorrow across the area as the amplification of the ridging is
maximized before a system moving eastward through the Pacific
northwest begins to flatten the ridge on Friday bringing
temperatures slightly cooler.
Another cutoff type low hanging out over the eastern Pacific and
originating from the Gulf of Alaska will move east over Southern
California late this weekend into the beginning of next week
bringing cooler temperatures close to normal levels and also
increasing chances of showers over the area. However, the best
chances will be the mountain areas of Kern County and along the
Sierra crest. Area winds with the system passage will become
breezy with wind favored areas becoming gusty. Depending on the
exact timing, it would not be out of the question to have a few
thunderstorms develop over the Kern County mountains and even
possibly over the Kern desert areas by Monday as the trough is
kicked east by a phasing of a northern system moving through the
jet that will be set up over the northern Continental U.S. Early next week.
A trough moving down with the jet is progged to move southward
over The Spine of the Sierra late Tuesday into Wednesday. This
will once again increase chances of precipitation for the Sierra
Nevada especially around Yosemite. Area winds will also increase. At
this time precipitation amounts look meager.
isolated showers and thunderstorms near the crest of the southern
Sierra Nevada are possible thru 03z Thu and again after 19z Thu.
Otherwise, VFR conditions will prevail across the central California
interior over the next 24 hours.
Air quality issues...
on Wednesday April 24 2019... unhealthy for sensitive groups in
Fresno and Kern counties.
Further information is available at valleyair.Org
The level of certainty for days 1 and 2 is high.
The level of certainty for days 3 through 7 is medium.
Certainty levels include low...medium...and high. Please visit
www.Weather.Gov/hnx/certainty.Html for additional information
an/or to provide feedback.